Lol, we don't die in heat waves, we are used to that kind of weather. Heat waves don't come on suddenly here like they can in regions where heat isn't usually a problem. We see 90 degree temps starting in March easily, and they last until November. Heat stroke happens because you're not acclimated to the hot weather, not just pure heat alone. The power has and does go out in the summer. So we go swimming or just get out of the house, not like in the winter when you're potentially iced in or driving conditions are unsafe. Sure it's miserable just sitting in a hot house, but it's not going to kill anyone here since we're used to it. And there aren't a lot of recreational ways to warm up like there are to cool down.
You may think it makes no sense, but not everyone has money to spend on a generator they may use a few days max out of the year. I'm certainly not planning on getting one any time soon, even with our current conditions. It doesn't make sense to have one sitting around that you don't NEED imo. Would it be smart? Probably, but it's just not necessary and no one has them because there's never a need for them. If this happened more often then maybe you'd see more people with them. Maybe some of the country folk have them, but in a city there's really no need.